Date: Mon, 13 Jul 2009 13:03:20 -0700 From: Nick Esborn <nick@desert.net> To: freebsd-current@freebsd.org Subject: MySQL thread deadlock, even after r195403 libthr fix Message-ID: <69315F2B-3F55-45B7-93AC-B75E678AB5C6@desert.net>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --Apple-Mail-3-772744607 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Hello, I am working with a 16-core Opteron server which runs five different MySQL 5.0 processes, each with different data sets on MyISAM tables, in jails. It ran flawlessly for about six months under 7.0. After upgrading from 7.0 to 7.2, one of the MySQL processes has begun exhibiting a serious problem. Within anywhere from several hours to a day or two after starting the process, a query thread will lock up. Output from procstat -k for such a thread: 3896 100795 mysqld - mi_switch sleepq_catch_signals sleepq_wait_sig _sleep do_rw_rdlock __umtx_op_rw_rdlock syscall Xfast_syscall Once this thread locks up, replication grinds to a halt, as the thread holds read locks. To unwedge the situation, I have to kill -9 the mysqld process, myisamchk the tables, and start the process back up again. 7.2-RELEASE-p2 did not resolve the problem. Late last week I upgraded to 8.0-BETA1 with the r195403 libthr fix, but that also failed to resolve the problem. Mind you, in every other way, 8.0 is amazing on this 16-core server. I had initially filed a bug report here: http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/135673 This was before the 16-core upgrade, and before trying 8.0. Subsequently, though, a conversation with Jeff Roberson helped me realize that it's more likely a kernel issue than a MySQL one. I hope this deadlock can be resolved. We really need 8.0's performance on this class of server. Thanks, -nick -- nick@desert.net - all messages cryptographically signed --Apple-Mail-3-772744607 content-type: application/pgp-signature; x-mac-type=70674453; name=PGP.sig content-description: This is a digitally signed message part content-disposition: inline; filename=PGP.sig content-transfer-encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Darwin) iEYEARECAAYFAkpbkwgACgkQw1bX5UNr2ADrtgCfQC3/Yws0Sr134+SZOow0cEpR ebYAnjCLCxcbVWNkr5Fg/0U3Fwm5qgLb =fZle -----END PGP SIGNATURE----- --Apple-Mail-3-772744607--
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